Contaminants of Concern in Cannabis: Microbes, Heavy Metals and Pesticides

Abstract

Microbiological contaminants pose a potential threat to cannabis consumers. Bacteria and fungi may cause opportunistic infections in immunocompromized individuals. Even dead organisms may trigger allergies and asthma. Toxins from microbial overloads, such as Shigla toxin and aflatoxins, may pose a problem—unlikely, but possible. The Cannabis plant hosts a robust microbiome; the identification of these organisms is underway. Cannabis bioaccumulates heavy metals in its tissues, so avidly that hemp crops have been used for bioremediation. Heavy metals cause myriad human diseases, so their presence in crops destined for human consumption must be minimized. Pesticide residues in cannabis pose a unique situation among crop plants—the Environmental Protection Agency (EPA) will not propose pesticides guidelines, because Cannabis is illegal on the federal level. The use of illegal pesticides is a rising crisis, and a breakdown in ethics. Testing for pesticide residues and maximal limits are proposed.